An MRI taken during the visit Friday showed flexor tendon damage in the right forearm, Boston manager John Farrell said. If an operation is performed, Hanrahan would miss the rest of the season and face the possibility of Tommy John surgery if damage is found to the ulnar collateral ligament of the elbow.

Ligament damage has been ruled out “to a certain extent,” Farrell said before Friday night’s game against the Toronto Blue Jays, “but in situations such as these type, once they have the ability to open up the arm and look at it directly, then they can make a more clear decision at that time if, in fact, Tommy John is needed.”

Hanrahan could choose to rest and rehabilitate the injury but still would miss at least two months. He was transferred on Thursday from the 15-day to the 60-day disabled list.

“Everything that shows right now is it’s the flexor tendon” that’s injured, Farrell said.

He also said Hanrahan hasn’t indicated when he’ll decide his course of treatment.

“In situations like this, it’s not uncommon for the player to make the final decision,” Farrell said. “Certainly, it’s his career, it’s his arm. Recommendations can be given through multiple opinions that he’s already received and I think he’s doing a very good job of getting his arms around it with the information gathered so that decision will become more clear-cut in Joel’s mind.”

Hanrahan went on the 15-day disabled list Tuesday before Thursday’s move.

The Red Sox acquired Hanrahan last Dec. 26 in a trade with the Pittsburgh Pirates. He was named an NL All-Star the past two seasons when he totaled 76 saves. But he’s 0-1 with a 9.82 ERA and four saves in six opportunities this season.

“Joel has talked about having some discomfort back in 2009,” Farrell said.

But he said that wasn’t a concern when the trade was made because Hanrahan didn’t miss time the next three years.

“I’ve got to believe (with) the number of years he’s pitched (that the injury) is probably a cumulative effect,” Farrell said, “and then, ultimately, as we saw on one pitch the other night.”

Hanrahan faced four batters in Boston’s 6-5 win in 11 innings over the Minnesota Twins on Monday night. He retired Ryan Doumit on a fly to left field, gave up a tying homer to Brian Dozier, struck out Joe Mauer and walked Josh Willingham. Then he was replaced by Clayton Mortensen.

Andrew Bailey, who became the closer when Hanrahan was on the disabled list from April 14-29 with a strained right hamstring, went on the 15-day DL on Monday with a strained right biceps.

Bailey threw for the second straight day on Friday, from 105 feet, but Farrell said no timetable has been set for when he’ll throw from a mound.

“There’s no date marked for his return,” Farrell said, “but we still feel confident with the group that we’ve got in our pen right now.”